Generator, wind turbine, method of assembling a generator and use of a generator in a wind turbine

Abstract

A generator is provided comprising a rotor with a number of magnetic rotor pole shoes, a stator with a number of stator coils wound on the stator, and a generator-utility grid interface comprising a plurality of diode rectifiers, each diode rectifier is connected to a stator coil and the number of stator coils is greater than the number of rotor pole shoes, or the number M of rotor pole shoes is greater than, but not an integer multiple of, the number of stator coils. A wind turbine utilizing the generator of the present invention and a method of assembling such a generator are provided.

The invention claimed is: 
     
       1. A generator, comprising
 a rotor with a number of magnetic rotor pole shoes; 
 a stator with a number of stator coils wound on the stator; and 
 a generator-utility grid interface comprising diode rectifiers, each one of the diode rectifiers connected to a stator coil and having an output; 
 wherein a number of rotor pole shoes is not equal to a number of stator coils and the number of rotor pole shoes is not an integer multiple of the number of stator coils; 
 wherein the diode rectifiers comprise a first, second and third plurality of diode rectifiers; 
 a first plurality of diode rectifier outputs connected in parallel to a first phase conductor for supplying a first plurality of AC rectified voltages to the first phase conductor, a second plurality of diode rectifier outputs connected in parallel to a second phase conductor for supplying a second plurality of AC rectified voltages to the second phase conductor, and a third plurality of diode rectifier outputs connected in parallel to a third phase conductor for supplying a third plurality of AC rectified voltages to the third phase conductor; and 
 each one of the first, second and third plurality of AC rectified voltages temporally shifted relative to other ones of the respective first, second and third plurality of AC rectified voltages, the temporal shift due to a relationship between the number of rotor pole shoes and stator coils, the temporal shift causing an essentially DC voltage to be present on each one of the first, second and third phase conductors. 
 
     
     
       2. The generator according to  claim 1 , wherein the stator coils and the rotor pole shoes are arranged such that at least a fraction of the rotor pole shoes pass stator coils asynchronously during rotation. 
     
     
       3. The generator according to  claim 1 , wherein the stator coils are assigned to different phases of a multi-phase utility grid, to which the generator is electrically connected. 
     
     
       4. The generator according to  claim 1 , wherein a group of stator coils share a common diode rectifier when these coils are assigned to a common phase and, during rotation of the rotor, each coil of the group carries a synchronous identical voltage form over time. 
     
     
       5. The generator according to  claim 1 , wherein each stator coil is connected to its own diode rectifier. 
     
     
       6. The generator according to  claim 1 , wherein each of the plurality of diode rectifiers share a common neutral. 
     
     
       7. The generator according to  claim 1 , wherein each of the plurality of diode rectifiers comprises a bridge rectifier. 
     
     
       8. The generator according to  claim 1 , wherein each of the plurality of diode rectifiers comprises at most two diodes. 
     
     
       9. The generator according to  claim 1 , wherein each of the plurality of diode rectifiers are mounted on the stator. 
     
     
       10. The generator according to  claim 1 , wherein the number of stator coils and the number of rotor pole shoes are selected such that the output voltages are induced in different stator coils during rotation of the rotor are temporally shifted against each other. 
     
     
       11. A wind turbine, comprising a generator according to any  claim 1 . 
     
     
       12. A method of assembling a generator, comprising:
 configuring a rotor with a number of magnetic rotor pole shoes, 
 configuring a stator with a number of stator coils wound on the stator, the number of stator coils not equal to a number of rotor pole shoes and the number of rotor pole shoes not an integer multiple of the number of stator coils; 
 assembling the stator with the rotor and with a generator-utility grid interface, the generator-utility grid interface is equipped with diode rectifiers in which each of the diode rectifiers is connected to a stator coil each diode rectifier having an output; 
 wherein the diode rectifiers comprise a first, second and third plurality of diode rectifiers; 
 configuring a first plurality of diode rectifier outputs in parallel and connecting to a first phase conductor for supplying a first plurality of AC rectified voltages to the first phase conductor, configuring a second plurality of diode rectifier outputs in parallel and connecting to a second phase conductor for supplying a second plurality of AC rectified voltages to the second phase conductor, and configuring a third plurality of diode rectifier outputs in parallel and connecting to a third phase conductor for supplying a third plurality of AC rectified voltages to the third phase conductor; and 
 each one of the first, second and third plurality of AC rectified voltages temporally shifted relative to other ones of the respective first, second and third plurality of AC rectified voltages, the temporal shift due to a relationship between the number of rotor pole shoes and stator coils, the temporal shift causing an essentially DC voltage to be present on each one of the first, second and third phase conductors.